A well built man armed with a handgun has stolen a sum of money from a post office in Limavady, police have said.
The thief entered the premises on the Drumsurn Road in the town shortly before 10am on Monday.
He is understood to have been carrying what appeared to be a handgun. He forced staff to hand over an undisclosed amount of cash.
Police say he may have made his escape in a getaway car.
The man has been described as wearing a khaki jacket and being well built. Local police have appealed for anyone who witnessed the robbery to pass on information.
Sinn Féin MLA for East Londonderry Billy Leonard said local post office in a rural area provides a vital service.
"This robbery has really shocked the Postmistress Brenda Chivers and a customer who happened to be in getting his pension. These people should be allowed the basic right of going about their business without fear of this type of incident", Mr Leonard said.
"I hope that both will be able to bounce back from this dreadful event.
"A local post office in a rural area is such a vital community service yet we have to admit they are vulnerable and unfortunately there are some people who will exploit that."
© UTV News